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Journal articles on the topic 'Pyrochlore structure'

Author: Grafiati

Published: 2 June 2025

Last updated: 31 July 2025

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1

Parshukova, K. N., E. P. Rylchenko, V. A. Muraviev, et al. "SYNTHESIS OF MULTICOMPONENT COMPOUNDS WITH A PIROCHLORE-TYPE STRUCTURE." Steklo i Keramika, no. 10 (October 2022): 34–39. http://dx.doi.org/10.14489/glc.2022.10.pp.034-039.

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The possibility of solid-phase synthesis of multicomponent bismuth niobates and tantalates with pyrochlore-type structure (sp. gr. Fd-3m), containing atoms of transition 3d-elements in equimolar quantities is shown. The composition of this type pyrochlores can be described by stoichiometric formula Bi2Cr1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6Ta(Nb)2O9 ± ?. A feature of synthesis of pyrochlores is a multi-stage high-temperature heat treatment process at a temperature of 650, 850, 950, 1050 °С for 60 hours. In the case of bismuth tantalate based pyrochlore, impurity phase of triclinic bismuth orthotantalat

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2

Rushton, M. J. D., Robin W. Grimes, C. R. Stanek, and Scott Owens. "Predicted pyrochlore to fluorite disorder temperature for A2Zr2O7 compositions." Journal of Materials Research 19, no. 6 (2004): 1603–4. http://dx.doi.org/10.1557/jmr.2004.0231.

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In a previous publication the order–disorder pyrochlore to fluorite transformation temperatures for a series of A2Hf2O7 pyrochlores were predicted [C.R. Stanek and R.W. Grimes: Prediction of rare-earth A2Hf2O7 pyrochlore phases. J. Am. Ceram. Soc. 2002, 85, p. 2139]. This was facilitated by establishing a relationship between these temperatures and the energy required to introduce a specific defect structure into the perfect pyrochlore lattice. Here an equivalent relationship for A2Zr2O7 pyrochlores was generated, and from this the disorder temperatures for a number of compositions including E

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3

Livshits, Tatiana, Sergey Yudintsev, Sergey V. Stefanovsky, and Rodney Charles Ewing. "New Actinide Waste Forms with Pyrochlore and Garnet Structures." Advances in Science and Technology 73 (October 2010): 142–47. http://dx.doi.org/10.4028/www.scientific.net/ast.73.142.

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Cubic oxides with pyrochlore and garnet structures are promising matrices for long-lived actinides immobilization. Their isomorphic capacity with respect to An and REE was determined. To predict the long-term behavior of these matrices under their underground disposal radiation stability of synthetic pyrochlores and garnets was studied. Most of titanate phases have the critical (amorphization) doses close to 0.2 displacements per atom at 298 K. This value is significantly higher for Sn- and Zr-rich pyrochlores. Corrosion behavior of the pyrochlore- and garnet-composed matrices was investigated

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4

Wang, Yuhao, Chong Jing, Zhao-Ying Ding, et al. "The Structure, Property, and Ion Irradiation Effects of Pyrochlores: A Comprehensive Review." Crystals 13, no. 1 (2023): 143. http://dx.doi.org/10.3390/cryst13010143.

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Since the beginning of the use of nuclear energy, humans have been faced with the problem of radionuclide disposal. At present, a large amount of waste is stored in pools or dry tanks at reactor sites. With the development of the nuclear power generation industry worldwide, the high storage cost (including building, maintaining, and operating storage pools) is overwhelming and serious, and urgent radionuclide disposal problems have become increasingly difficult. Safe and economical strategies are urgently needed for long-term storage and disposal of nuclear waste, which has become among the co

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5

Khanvilkar, M. B., A. K. Nikumbh, S. M. Patange, et al. "Structural, electrical and magnetic properties of substituted pyrochlore oxide nanoparticles synthesized by the co-precipitation method." Physics and Chemistry of Solid State 22, no. 2 (2021): 353–71. http://dx.doi.org/10.15330/pcss.22.2.353-371.

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Five substituted pyrochlore nanooxides such as Nd1.9Ho0.1Zr1.8Ce0.2O7, La1.95Ce0.05Zr0.29Ce1.71O7, Y1.79Pr0.21Ru1.99Pr0.01O7, Dy1.9Yb0.1Mn1.93Cu0.07O7 and Dy1.99Sr0.01Sn2O7 were synthesized by coprecipitation method. These precursors were monitored by thermal studies (TGA-DTA). The prepared nanosized substituted pyrochlore oxides were characterized by EDS, XRD, SEM, TEM, d. c. electrical conductivity, Thermoelectric power, Hall effect measurement, dielectric properties and magnetization measurements. XRD confirmed the formation of a single phase crystalline substituted pyrochlores with a cubic

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6

Petrakov, A. P., K. A. Badanina, A. A. Selyutin та ін. "Research of the properties of a complex oxide Bi2Co1/3Cu1/3Ni1/3Nb2O9+Δ with a pyrochlore structure". Industrial laboratory. Diagnostics of materials 91, № 5 (2025): 38–44. https://doi.org/10.26896/1028-6861-2025-91-5-38-44.

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Bismuth-containing monodoped pyrochlores have promising photocatalytic and dielectric properties. The paper presents the results of studying the properties of multielement pyrochlore containing transition 3d-elements in equivalent amounts. Mixed oxide pyrochlore of the composition Bi2Co1/3Cu1/3Ni1/3Nb2O9+Δ (sp. gr. Fd-3m, a = 10.5378 ± 6 Å) was synthesized by the solid-phase reaction method. The chemical state of transition element cations in the oxide pyrochlore was estimated by X-ray photoelectron spectroscopy (XPS). The parameters of the Bi5d, Nb3d, Co2p, Ni2p, Cu2p XPS spectra for the mixe

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7

Zhuk, Nadezhda A., Sergey V. Nekipelov, Olga V. Petrova, et al. "Synthesis, Phase Formation, and Raman Spectroscopy of Ni and Zn(Mg) Codoped Bismuth Stibate Pyrochlore." Chemistry 7, no. 4 (2025): 110. https://doi.org/10.3390/chemistry7040110.

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Complex antimony pyrochlores Bi2.7M0.46Ni0.70Sb2O10+Δ (M = Zn, Mg) were synthesized from oxide precursors, using the solid-state reaction method. For each composition variant, the pyrochlore phase formation process was studied during solid-state synthesis in the range of 500–1050 °C. The influence of zinc and magnesium on the phase formation process was established. The interaction of oxide precursors occurs at a temperature of 600 °C and higher, resulting in the formation of bismuth stibate (Bi3SbO7) as a binary impurity phase. Oxide precursors, including bismuth(III) and antimony(III,V) oxid

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8

Tan, Phei, Kar Tan, Chwin Khaw, et al. "Substituted Bi3.5Mg1.8Nb2.7O13.8 pyrochlores with transition metals (Zn, Ni and Cd): Doping mechanism, structure and electrical properties." Processing and Application of Ceramics 18, no. 3 (2024): 281–89. http://dx.doi.org/10.2298/pac2403281t.

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The influence of transition metals (Zn, Cd and Ni) on bismuth magnesium niobate (Bi3.5Mg1.8Nb2.7O13.8, BMN) pyrochlores was investigated. Considering the difference in their ionic radii, Cd was postulated to substitute Mg at the eight-fold coordinated A-site whereas Zn and Ni were to replace Mg at the six-fold coordinated B-sites of the host structure. Solubility limits in these substitutional pyrochlore solid solutions were determined to be 0.4, 0.1 and 0.3 for Zn, Ni and Cd, respectively. Upon introducing these divalent cation dopants, notable changes in the lattice parameters and grain size

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9

Zhou, Haidong, and Christopher Wiebe. "High-Pressure Routes to New Pyrochlores and Novel Magnetism." Inorganics 7, no. 4 (2019): 49. http://dx.doi.org/10.3390/inorganics7040049.

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The pyrochlore structure (A2B2O7) has been an object of consistent study by materials scientists largely due to the stability of the cubic lattice with respect to a wide variety of chemical species on the A or B sites. The criterion for stability under ambient conditions is controlled by the ratio of these cations, which is empirically 1.36 < RA/RB < 1.71. However, under applied pressure synthesis conditions, the pyrochlore lattice is stable up to RA/RB ∼ 2.30, opening up possibilities for new compounds. In this review, we will highlight recent work in exploring new rare-earth pyrochlore

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10

Xue, Yuan, Ningyue Sun, and Guowu Li. "Evolution of Nb–Ta Oxide Minerals and Their Relationship to the Magmatic-Hydrothermal Processes of the Nb–Ta Mineralized Syenitic Dikes in the Panxi Region, SW China." Minerals 11, no. 11 (2021): 1204. http://dx.doi.org/10.3390/min11111204.

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Previous geochemical and petrological studies have concluded that initially magmatic Nb–Ta mineralization is often modified by post-magmatic hydrothermal fluids; however, there is still a lack of mineralogical evidence for the syenite-related Nb–Ta deposit. From the perspective of Nb–Ta minerals, the pyrochlore supergroup minerals have significance for indicating the fluid evolution of alkaline rock or related carbonatite type Nb–Ta deposits. The Panzhihua–Xichang (Panxi) region is a famous polymetallic metallogenic belt in southwestern China, abound with a huge amount of Nb–Ta mineralized sye

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11

Wang, Hong, Desheng Zhang, Xiaoli Wang, and Xi Yao. "Effect of La2O3 substitutions on structure and dielectric properties of Bi2O3–ZnO–Nb2O5-based pyrochlore ceramics." Journal of Materials Research 14, no. 2 (1999): 546–48. http://dx.doi.org/10.1557/jmr.1999.0078.

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The effect of La2O3 substitutions on structure and dielectric properties of Bi2O3 –ZnO–Nb2O5-based ceramics was investigated. Bi1.5-xLaxZn0.5(Zn0.5Nb1.5)O7 samples were prepared by conventional ceramic processing technology. The crystal structure of the Bi1.5Zn0.5(Zn0.5Nb1.5)O7 sample was characterized as a pure cubic pyrochlore. With a lower amount of La2O3 substitution, the crystal structures were still cubic pyrochlore. Superlattice x-ray diffraction line was identified for some compositions. With the increasing amount of La2O3 substitution, the crystal structure gradually transformed from

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12

HARRIS, M. J., and M. P. ZINKIN. "FRUSTRATION IN THE PYROCHLORE ANTIFERROMAGNETS." Modern Physics Letters B 10, no. 10 (1996): 417–38. http://dx.doi.org/10.1142/s021798499600047x.

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In an antiferromagnet with the pyrochlore structure, the magnetic ions are situated on a framework of corner-sharing tetrahedra. This lattice results in a high degree of geometrical frustration, and theoretical studies predict that the magnetic ground state is continuously disordered. The majority of pyrochlore compounds are observed to remain disordered down to the lowest temperatures, and susceptibility measurements show that they often behave as conventional spin glasses. Neutron diffraction studies have discovered strong magnetic diffuse scattering at low temperatures. This reveals the pre

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13

Rapenne, L., C. Jiménez, T. Caroff, et al. "High-resolution transmission electron microscopy observations of La2Zr2O7 thin layers on LaAlO3 obtained by chemical methods." Journal of Materials Research 24, no. 4 (2009): 1480–91. http://dx.doi.org/10.1557/jmr.2009.0162.

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La2Zr2O7 (LZO) films have been grown by metalorganic decomposition (MOD) to be used as buffer layers for coated conductors. LZO can crystallize into two similar structures: fluorite or pyrochlore. Coated conductor application focuses on pyrochlore structure because it is a good barrier against oxygen diffusion. Classical x-ray diffraction is not able to separate the contribution of these two structures. Transmission electron microscopy and high-resolution transmission electron microscopy were used to determine the local distribution of these two phases in epitaxial LZO layers grown on LaAlO3.

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14

Viladkar, Shrinivas G., and Natalia V. Sorokhtina. "Evolution of pyrochlore in carbonatites of the Amba Dongar complex, India." Mineralogical Magazine 85, no. 4 (2021): 554–67. http://dx.doi.org/10.1180/mgm.2021.50.

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AbstractPyrochlore-group minerals are common accessory rare-metal bearing minerals in the calcite and ankerite carbonatites of the Amba Dongar complex (India). Pyrochlore from the Amba Dongar carbonatites differs from that in other Indian complexes in Ta, Zr, Ti, rare earth element (REE) and Pb contents, but is similar with respect to Ca, Ba and Sr abundances. The evolution of pyrochlore composition was studied to understand the alteration processes and the formation of late-stage pyrochlores enriched in REE and Pb. The early magmatic pyrochlore are calcio- and niobium-dominant types and were

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15

Lian, Jie, Rodney C. Ewing, L. M. Wang, and K. B. Helean. "Ion-beam irradiation of Gd2Sn2O7 and Gd2Hf2O7 pyrochlore: Bond-type effect." Journal of Materials Research 19, no. 5 (2004): 1575–80. http://dx.doi.org/10.1557/jmr.2004.0178.

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Ceramics with III-IV pyrochlore compositions, A3+2B4+2O7 (A = Y and rare earth elements; B = Ti, Zr, Sn, or Hf), show a wide range of responses to ion-beam irradiation. To evaluate the role of the B-site cations on the radiation stability ofthe pyrochlore structure-type, Gd2Sn2O7 and Gd2Hf2O7 have been irradiated by1 MeV Kr+. The results are discussed in terms of the ionic size and type ofbonding of Sn4+ and Hf4+ and compared to previous results for titanate andzirconate pyrochlores. Gd2Sn2O7 is sensitive to ion beam–induced amorphizationwith a critical amorphization dose of approximately 3.4

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16

Muravyov, Vitaliy A., Maria G. Krzhizhanovskaya, Boris A. Makeev, et al. "Features of the Preparation of Ni-Doped Bismuth Tantalate Pyrochlore." Crystals 13, no. 3 (2023): 474. http://dx.doi.org/10.3390/cryst13030474.

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The possibility of high-temperature solid-phase synthesis of Ni-doped bismuth tantalate pyrochlore, not only from the oxide compounds BiTaO4 and NiO but also using nickel chloride NiCl2 as a precursor, was shown for the first time. The concentration range of the formation of nickel pyrochlore Bi2NixTa2O9−δ (0.85 ≤ x ≤ 1.0) at an equal molar ratio of bismuth(III)/tantalum(V) ions was determined. This indicates that the pyrochlore structure may be stable at 20–33% vacant bismuth sublattice. The influence of non-stoichiometric composition relative to bismuth and tantalum, by the example of Bi2±xN

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17

Heath, Megan Muriel, Elise Fosdal Closs, Svein Sunde, et al. "The Potential of Ruthenate Pyrochlores As Anodic Electroctalysts for PEM Water Electrolysisoral Presentation." ECS Meeting Abstracts MA2024-02, no. 42 (2024): 2847. https://doi.org/10.1149/ma2024-02422847mtgabs.

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Green hydrogen is becoming a hot commodity in the light of escalating oil and gas prices and their uncertain future availability. Among various electrolysis technologies, PEM water electrolysis (WE) is favorable for its portability, modularity, and the ability to integrate with intermittent, renewable energy sources. However, the upscaling of PEMWE is not feasible yet due to the need for rare and expensive metals as electrocatalysts. Specifically, iridium oxide is used as state-of-the art anodic electrocatalyst. Ruthenium oxide also has an excellent activity towards the anodic oxygen evolution

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18

Lumpkin, G. R., and R. C. Ewing. "Alpha-decay damage and the aperiodic structure of pyrochlore." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 470–71. http://dx.doi.org/10.1017/s0424820100104418.

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Alpha-decay damage in minerals which contain U and Th involves two separate damage processes: a high energy (4-5 MeV) alpha particle with a range of 10,000 nm displaces several hundred atoms creating Frenkel defects near the end of die track; and a recoil atom (0.1 MeV) with a range of 10 nm produces several thousand atomic displacements creating “tracks” of disordered material. Pyrochlore group minerals are suitable for the study of alpha-decay damage because they contain variable amounts of U and Th such that the accumulated dose spans the transition from the crystalline to the fully aperiod

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19

Muraviev, V. A., B. A. Makeev, M. G. Krzhizhanovskaya, R. I. Korolev, and N. A. Zhuk. "SYNTHESIS OF Bi2NiTa2O9 WITH A PYROCHLORE-TYPE STRUCTURE." Steklo i Keramika, no. 2 (February 2022): 40–46. http://dx.doi.org/10.14489/glc.2022.02.pp.040-046.

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Nickel pyrochlore of the composition Bi2NiTa2O9 was synthesized by the solid-phase reaction method (sp. gr. Fd-3m, a = 10.5238 Å). The process of phase formation of nickel-containing bismuth tantalate Bi2NiTa2O9 with a pyrochlore structure is investigated. The pyrochlore phase synthesis reaction is described by the interaction of orthorhombic bismuth orthotantalate and nickel oxide. Synthesis proceeds mainly at temperatures above 900 °С. The duration of calcination of the preparations leads to the coalescence of grains with the formation of larger particles. The calcination temperature did not

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20

Matsunami, M., T. Hashizume, and A. Saiki. "Ion-Exchange Reaction Of A-Site In A2Ta2O6 Pyrochlore Crystal Structure." Archives of Metallurgy and Materials 60, no. 2 (2015): 941–44. http://dx.doi.org/10.1515/amm-2015-0234.

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Abstract Na+ or K+ ion rechargeable battery is started to garner attention recently in Place of Li+ ion cell. It is important that A+ site ion can move in and out the positive-electrode materials. When K2Ta2O6 powder had a pyrochlore structure was only dipped into NaOH aqueous solution at room temperature, Na2Ta2O6 was obtained. K2Ta2O6 was fabricated from a tantalum sheet by a hydrothermal synthesize with KOH aqueous solution. When Na2Ta2O6 was dipped into KOH aqueous solution, K2Ta2O6 was obtained again. If KTaO3 had a perovskite structure was dipped, Ion-exchange was not observed by XRD. Be

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21

Wang, Hong, and Xi Yao. "Structure and dielectric properties of pyrochlore–fluorite biphase ceramics in the Bi2O3–ZnO–Nb2O5 system." Journal of Materials Research 16, no. 1 (2001): 83–87. http://dx.doi.org/10.1557/jmr.2001.0016.

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The structure and dielectric properties of Bi2O3–ZnO–Nb2O5-based ceramics with pyrochlore–fluorite biphase structure were investigated. Mixed-sintered ceramics were prepared by two precalcined constituents in the system of x[Bi1.5Zn0.5(Zn0.5Nb1.5)O7]−(1 − x)Bi3/4Nb1/4O7/4 (0.05 ≤ x ≤ 0.35), where Bi1.5Zn0.5(Zn0.5Nb1.5)O7 is a cubic pyrochlore (α) and Bi3/4Nb1/4O7/4 is a defect cubic fluorite (F). The phase composition of the mixed-sintered ceramics were characterized as a biphasic structure with a distorted pyrochlore (β) and a fluorite (F) coexisting. The phase ratio of β pyrochlore and F flu

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22

Tarassov, Mihail, and Eugenia Tarassova. "Conditions and Mechanism of Crystallization of Hydrous W-Fe Oxides with a Pyrochlore-Type of Structure (Elsmoreite Group) in the Oxidation Zone of Ore Deposits." Minerals 14, no. 4 (2024): 422. http://dx.doi.org/10.3390/min14040422.

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The purpose of the article is to elucidate the conditions and mechanism of crystallization of W-Fe oxide minerals with a pyrochlore-type structure (formerly ferritungstite, now elsmoreite group minerals) based on (1) a study of representative samples of secondary tungsten minerals from the oxidation zone of the Grantcharitsa tungsten deposit (Bulgaria) and (2) laboratory experiments under conditions suggested by the study of natural samples. It has been shown that crystallization of W-Fe pyrochlores occurs easily and effectively when treating WO3·xFe2O3·nH2O compounds (meymacite and tungstite)

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23

GUO, JING-DONG, and M. STANLEY WHITTINGHAM. "TUNGSTEN OXIDES AND BRONZES: SYNTHESIS, DIFFUSION AND REACTIVITY." International Journal of Modern Physics B 07, no. 23n24 (1993): 4145–64. http://dx.doi.org/10.1142/s0217979293003607.

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The tungsten oxides and bronzes have been extensively studied since their discovery in the last century, because of their brilliant colors and high electrical conductivity. More recently the driving interest resulted from their potential use in electrochromic displays and other electrochemical systems. Their crystalline structures are generally based on the corner sharing of WO 6 octahedra giving tunnels of variable size and shape leading to exciting intercalation chemistry. These structures readily undergo redox reactions, and in the last quarter century these reactions have often involved so

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24

Teng, Zhen, Yongqiang Tan, and Haibin Zhang. "High-Entropy Pyrochlore A2B2O7 with Both Heavy and Light Rare-Earth Elements at the A Site." Materials 15, no. 1 (2021): 129. http://dx.doi.org/10.3390/ma15010129.

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A novel class of high-entropy pyrochlore ceramics (HEPCs) with multiple heavy and light rare-earth elements at the A site were successfully synthesized via solid-state reaction. Both the XRD patterns and Raman spectroscopy demonstrated the single pyrochlore structure feature of seven kinds of HEPCs. Electron microscopic images revealed the typical morphology and the homogeneous distribution of all rare-earth elements. It can be concluded that the significance of configuration entropy in the HEPC system has promoted the tervalent lanthanide nuclides to form a single pyrochlore structure. This w

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25

Huang, Shih-Wen, Horng-Tay Jeng, J.-Y. Lin, et al. "Electronic structure of pyrochlore Cd2Re2O7." Journal of Physics: Condensed Matter 21, no. 19 (2009): 195602. http://dx.doi.org/10.1088/0953-8984/21/19/195602.

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Goh, Gregory K. L., Sossina M. Haile, Carlos G. Levi, and Fred F. Lange. "Hydrothermal synthesis of perovskite and pyrochlore powders of potassium tantalate." Journal of Materials Research 17, no. 12 (2002): 3168–76. http://dx.doi.org/10.1557/jmr.2002.0458.

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Potassium tantalate powders were hydrothermally synthesized at 100 to 200 °C in 4 to 15 M aqueous KOH solutions. A defect pyrochlore, Kta2O5(OH). nH2O (n ≈ 1.4), was obtained at 4 M KOH, but at 7–12 M KOH, this pyrochlore was gradually replaced by a defect perovskite as the stable phase. At 15 M KOH, there was no intermediate pyrochlore, only a defect perovskite, 0.85Ta0.92O2.43(OH)0.57 0.15H2O. Synthesis at higher KOH concentrations led to greater incorporation of protons in the perovskite structures. The potassium vacancies required for charge compensation of incorporated protons could accom

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27

Zhang, Fu Xiang, and Maik Lang. "Pressure-Induced Cationic Disordering in Pyrochlore Oxides (La_1-xCe_x)₂Zr₂O₇ and Enhancement of Compressibility." Advanced Materials Research 1033-1034 (October 2014): 583–87. http://dx.doi.org/10.4028/www.scientific.net/amr.1033-1034.583.

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Pyrochlore oxides La2Zr2O7,Ce2Zr2O7and their solid solutions were studied by in situ x-ray diffraction (XRD) measurement at high pressures. Pressure dependence of cationic disordering was derived from Rietveld refinement of the XRD patterns. The results indicated that the mixed occupancy in the cation site enhanced the compressibility obviously. All the pyrochlore structure became unstable at ~20 GPa and an orthorhombic high-pressure phase formed. The cations changed from the ordered state in pyrochlore to a disordered state in the high-pressure phase. The high-pressure phase is about 8% dense

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Lumpkin, G. R., and R. C. Ewing. "Transmission electron microscopy of alpha-decay damage and alteration of betafite." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 376–77. http://dx.doi.org/10.1017/s0424820100126676.

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The pyrochlore structure type occurs as a constituent of crystalline nuclear waste form assemblages proposed for the long term isolation of actinides. Betafite, the Ti-rich end-member of the pyrochlore group, is a natural analogue similar in composition to waste form pyrochlores. This study examines the effects of alpha-recoil damage and geochemical alteration on a specimen of betafite from Antanifotsy, Madagascar (Harvard no. 87876, UNM no. 205).Electron microprobe analyses were performed using a JEOL 733 Superprobe operated at 15 kV and 20 nA sample current crushed fragments of the sample we

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29

Fan, Long, Yi Xie, and Xiao Yan Shu. "Fabrication of Pyrochlore Gd₂Zr₂O₇by High Temperature Solid State Reaction." Advanced Materials Research 1061-1062 (December 2014): 87–90. http://dx.doi.org/10.4028/www.scientific.net/amr.1061-1062.87.

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In order to investigate the fabrication of pyrochlore Gd2Zr2O7, Gd2O3 and ZrO2 were used as raw materials in the process. Pyrochlore Gd2Zr2O7 were fabricated by high temperature solid state reaction at 1100 – 1600 °C under atmospheric pressure for 72 h. XRD and SEM studies were exploited to characterize the crystal structure and microstructure of the synthetic samples. The results revealed that Gd2Zr2O7 with a single pyrochlore structure was fabricated successfully at 1500 °C. The microstructure of the sample was uniform and dense, and the grain size was in the range of 1 - 3 μm.

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30

Kennedy, Brendan, Peter Blanchard, Emily Reynolds, and Zhaoming Zhang. "Transformation from pyrochlore to fluorite by diffraction and X-ray spectroscopy." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C234. http://dx.doi.org/10.1107/s2053273314097654.

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We have studied the long-range average and local structures in a number of zirconium containing materials of the type A2B2O7 ( A = Ln or Y; B = Zr, Hf or Sn) using synchrotron X-ray and neutron powder diffraction and X-ray absorption spectroscopy. Studies of the system Gd2-xTbxZr2O7 include neutron diffraction data, obtained at λ ≍ 0.497 Å to minimise absorption, not only provide evidence for independent ordering of the anion and cation sublattices, but also suggest that the disorder transition across the pyrochlore-defect fluorite boundary of Ln2Zr2O7 is rather gradual. In general we observe

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31

van de Velde, G. M. H., B. C. Lippens, S. J. Korf, and J. Boeijsma. "Powder Diffraction Data for the Imperfect Pyrochlore Terbium Titanate, Tb2Ti2O7." Powder Diffraction 5, no. 4 (1990): 229–31. http://dx.doi.org/10.1017/s088571560001589x.

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AbstractNotwithstanding expectations of a pure pyrochlore structure (cubic space group Fd3m (227) with Z=8) terbium titanate turns out, like many pyrochlore compounds, to be slightly disordered in the cation and the oxygen lattice so that it partially (for 10%) resembles a structure with fluorite properties (space group Fm3m (225) with Z = 2).

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Li, Pengcheng, Fengai Zhao, Haiyan Xiao, et al. "First-Principles Study of Thermo-Physical Properties of Pu-Containing Gd2Zr2O7." Nanomaterials 9, no. 2 (2019): 196. http://dx.doi.org/10.3390/nano9020196.

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A density functional theory plus Hubbard U method is used to investigate how the incorporation of Pu waste into Gd2Zr2O7 pyrochlore influences its thermo-physical properties. It is found that immobilization of Pu at Gd-site of Gd2Zr2O7 has minor effects on the mechanical and thermal properties, whereas substitution of Pu for Zr-site results in remarkable influences on the structural parameters, elastic moduli, elastic isotropy, Debye temperature and electronic structure. The discrepancy in thermo-physical properties between Gd2−yPuyZr2O7 and Gd2Zr2−yPuyO7 may be a result of their different str

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Chen, Yan, Nina Orlovskaya, Nicholas Miller, et al. "La_1.97Sr_0.03Zr₂O₇ Pyrochlore Powder for Advanced Energy Application." Advances in Science and Technology 62 (October 2010): 56–60. http://dx.doi.org/10.4028/www.scientific.net/ast.62.56.

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Materials with A2B2O7 (pyrochlore) structure have received a significant attention for their applications as new protonic conductors and materials used in electronic devices. One of the unique synthesis routes for La2Zr2O7 (pyrochlore) powders is the glycine-nitrate combustion method, which shows superior properties of the synthesized powder by using glycine as a complexing agent. The Sr doped La2Zr2O7 powders in pure pyrochlore structure were produced using this approach. Selected characteristics of the synthesized powders, such as crystal structure, lattice parameters, crystallite size, the

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Zhang, Rui, Qiang Xu, Wei Pan, Chun Lei Wan, Long Hao Qi, and He Zhuo Miao. "Structure and Ionic Conductivity of Ln₂Zr₂O₇-Type Rare Earth Zirconates." Key Engineering Materials 336-338 (April 2007): 420–23. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.420.

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Three rare earth zirconates (Sm2Zr2O7, Gd2Zr2O7 and Er2Zr2O7) were prepared by solid state reaction. The crystal structure and ionic conductivity of these zirconates were characterized by X-ray diffraction (XRD) and complex impedance spectroscopy. The results show that Sm2Zr2O7 exhibits single-phase pyrochlore structure and Er2Zr2O7 exhibits single-phase fluorite structure, while Gd2Zr2O7 has pyrochlore and fluorite structure. Among three zirconates, the ionic conductivity of Sm2Zr2O7 is highest, while that of Er2Zr2O7 is lowest.

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Ma, Ting Ting, Rui Shen Zhou, and Xia Li. "Synthesis of Pyrochlore-Type K₂Ta₂O₆ with High Photocatalytic Activity for Dye Degradation." Key Engineering Materials 680 (February 2016): 203–7. http://dx.doi.org/10.4028/www.scientific.net/kem.680.203.

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Pyrochlore-type potassium tantalate (K2Ta2O6 ) was successfully synthesized through a facile hydrothermal method. X-Ray diffraction and electron microscopy reveal that pure K2Ta2O6 consisting of a nanooctahedral structure could be obtained at 180°C for 24 h. The photocatalytic activities of K2Ta2O6 were examined using aqueous solutions under ultraviolet irradiation. The degradation result of the Rhodamine B dye indicated that the pyrochlore-type potassium tantalates exhibited a remarkably higher photocatalytic activity than the perovskite phase sample. This high photocatalytic activity is ascr

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Bespalko, Yuliya, Nikita Eremeev, Ekaterina Sadovskaya, et al. "Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure." Membranes 13, no. 6 (2023): 598. http://dx.doi.org/10.3390/membranes13060598.

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Synthesis and study of materials based on bismuth cerates and titanates were carried out. Complex oxides Bi1.6Y0.4Ti2O7 were synthesized by the citrate route; Bi2Ce2O7 and Bi1.6Y0.4Ce2O7—by the Pechini method. The structural characteristics of materials after conventional sintering at 500–1300 °C were studied. It is demonstrated that the formation of a pure pyrochlore phase, Bi1.6Y0.4Ti2O7, occurs after high-temperature calcination. Complex oxides Bi2Ce2O7 and Bi1.6Y0.4Ce2O7 have a pyrochlore structure formed at low temperatures. Yttrium doping of bismuth cerate lowers the formation temperatur

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Troyanchuk, I. O., N. V. Kasper, D. D. Khalyavin, H. Szymczak, and A. Nabialek. "Magnetotransport properties of with pyrochlore structure." Journal of Physics: Condensed Matter 10, no. 2 (1998): 401–5. http://dx.doi.org/10.1088/0953-8984/10/2/019.

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Taira, Nobuyuki, Makoto Wakeshima, Yukio Hinatsu, Aya Tobo, and Kenji Ohoyama. "Magnetic structure of pyrochlore-type Er2Ru2O7." Journal of Solid State Chemistry 176, no. 1 (2003): 165–69. http://dx.doi.org/10.1016/s0022-4596(03)00384-0.

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Mitrofanova, Anna V., Elena A. Fortalnova, Marina G. Safronenko, Ekaterina D. Politova, and Alexandr V. Mosunov. "PHASE FORMATION AND PROPERTIES OF BISMUTH FERROTITANATES SUBSTITUTED BY HEAVY LANTHANIDE IONS (Tb, Er, Ho, Yb)." ChemChemTech 68, no. 1 (2024): 48–54. https://doi.org/10.6060/ivkkt.20256801.7085.

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The purpose of this study was to investigate the effect of cation substitutions on the formation of Aurivillius phases at various annealing temperatures using solid-state synthesis. The phase formation of lanthanide bismuth ferrotitanates with the Aurivillius phase structure Ln2Bi3FeTi3O15, where Ln = Tb, Ho, Er, Yb, has been studied. The obtained samples were characterized by X-ray diffraction, infrared spectroscopy, differential thermal and thermogravimetric analysis, and their elemental composition was studied. The predominant formation of a phase with a pyrochlore structure was revealed in

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Douma, Mohamed, Hossain El, Raquel Trujillano, and Vicente Rives. "Structural determination of new solid solutions [Y2-xMx][Sn2-xMx]o7-3x/2 (M = Mg or Zn) by Rietveld method." Processing and Application of Ceramics 4, no. 4 (2010): 237–43. http://dx.doi.org/10.2298/pac1004237d.

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New [Y2-xMx][Sn2-xMx]O7-3x/2 (0 ?x? 0.30 for M = Mg and 0 ?x? 0.36 for M = Zn) solid solutions with the pyrochlore structure were synthesized via high-temperature solid-state reaction method. Powder X-ray diffraction (PXRD) patterns and Fourier transform infrared (FT-IR) spectra showed that these materials are new non-stoichiometric solid solutions with the pyrochlore type structure. The structural parameters for the solids obtained were successfully determined by Rietveld refinement based on the analysis of the PXRD diagrams. Lattice parameter (a) of these solid solutions decreases when x inc

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Shlyakhtina, Anna V., Nikolay V. Lyskov, Galina E. Nikiforova, et al. "Proton Conductivity of La2(Hf2−xLax)O7−x/2 “Stuffed” Pyrochlores." Applied Sciences 12, no. 9 (2022): 4342. http://dx.doi.org/10.3390/app12094342.

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The design of new oxygen- and proton-conducting materials is of paramount importance for their possible utilization in solid oxide fuel cells. In the present work, La2(Hf2–xLax)O7–x/2 (x = 0, 0.1) ceramics were prepared using ball milling of oxide mixtures (La2O3 and HfO2) followed by high-temperature annealing at 1600 °C for 10 h in air. La2Hf2O7 ceramics exhibit an ordered pyrochlore-type structure, whereas La2(Hf1.9La0.1)O6.95 has a defect pyrochlore structure type with oxygen vacancies at the 48f positions. The oxygen ion and proton conductivity of La2(Hf1.9La0.1)O6.95 “stuffed” pyrochlore

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Shlyakhtina, Anna V., Nikolay V. Lyskov, Galina E. Nikiforova, et al. "Proton Conductivity of La2(Hf2−xLax)O7−x/2 “Stuffed” Pyrochlores." Applied Sciences 12, no. 9 (2022): 4342. http://dx.doi.org/10.3390/app12094342.

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The design of new oxygen- and proton-conducting materials is of paramount importance for their possible utilization in solid oxide fuel cells. In the present work, La2(Hf2–xLax)O7–x/2 (x = 0, 0.1) ceramics were prepared using ball milling of oxide mixtures (La2O3 and HfO2) followed by high-temperature annealing at 1600 °C for 10 h in air. La2Hf2O7 ceramics exhibit an ordered pyrochlore-type structure, whereas La2(Hf1.9La0.1)O6.95 has a defect pyrochlore structure type with oxygen vacancies at the 48f positions. The oxygen ion and proton conductivity of La2(Hf1.9La0.1)O6.95 “stuffed” pyrochlore

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43

Lang, M., F. X. Zhang, R. C. Ewing, Jie Lian, Christina Trautmann, and Zhongwu Wang. "Structural modifications of Gd2Zr2-xTixO7 pyrochlore induced by swift heavy ions: Disordering and amorphization." Journal of Materials Research 24, no. 4 (2009): 1322–34. http://dx.doi.org/10.1557/jmr.2009.0151.

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The isometric, pyrochlore structure type, A2B2O7, exhibits a wide variety of properties that find application in a large number of different technologies, from electrolytes in solid oxide fuel cells to actinide-bearing compositions that can be used as nuclear waste forms or inert matrix nuclear fuels. Swift xenon ions (1.43 GeV) have been used to systematically modify different compositions in the Gd2Zr2-xTixO7 binary at the nanoscale by radiation-induced phase transitions that include the crystalline-to-amorphous and order-disorder structural transformations. Synchrotron x-ray diffraction, Ra

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44

Moroz, Y., M. Lozynskyy, A. Lopanov, K. Chebyshev, and V. Burkhovetsky. "THE RESEARCH OF THE THERMOLYSIS PRODUCTS OF CESIUM TUNGSTOPHOSPHATES." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 5, no. 12 (2021): 126–35. http://dx.doi.org/10.34031/2071-7318-2020-5-12-126-135.

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The article deals with the synthesis, study of thermal decomposition and identification of the thermolysis products of cesium tungstophosphates that are promising compounds in the field of materials science, catalysis and other fields of science and technology. Compounds with the Keggin anion structure are synthesized from aqueous solutions: Cs3[PW12O40] ∙ 9H2O; Cs5Na2[PW11O39(H2O)] ∙ 5H2O and Cs5[PW11O39Ni0,5Cu0,5(H2O)] ∙ 4H2O. The processes of their thermal decomposition are investigated and some regularities of their thermolysis are established. Thermolysis products are identified: Cs

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Finkeldei, S., M. C. Stennett, P. M. Kowalski, et al. "Insights into the fabrication and structure of plutonium pyrochlores." Journal of Materials Chemistry A 8, no. 5 (2020): 2387–403. http://dx.doi.org/10.1039/c9ta05795a.

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Peters, E., and Hk Müller-Buschbaum. "Synthese eines Pyrochlors mit TiII: (Ta0.67TiII0.33)2Sm2O7/ Synthesis of a Pyrochlore Containing TiII: (Ta0.67TiII0.33)2Sm2O7." Zeitschrift für Naturforschung B 50, no. 9 (1995): 1340–42. http://dx.doi.org/10.1515/znb-1995-0907.

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AbstractHigh temperature reactions using a CO2-LASER led to a TiII containing phase of the composition (Ta0.67TiII0.33Sm2O7, space group O7h - Fd3̄m (No. 227), a = 10.385(2) Å . The oxidation state TiII which is stabilized by incorporation into the cubic pyrochlore structure was proved by the statistical occupation of the 16c point position by a Ta:Ti ratio of 2:1.

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Withers, RL, JG Thompson, PJ Barlow, and JC Barry. "The Defect Fluorite Phase in the ZrO2-PrO1.5 System and Its Relationship to the Structure of Pyrochlore." Australian Journal of Chemistry 45, no. 9 (1992): 1375. http://dx.doi.org/10.1071/ch9921375.

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A detailed transmission electron microscope and X-ray powder diffraction study has been made of the so-called 'defect fluorite' phase field in the ZrO2-PrO1.5 system and of its close relationship to the pyrochlore solid solution field in the same system. Even for the lowest possible PrO1.5 content within the 'defect fluorite' phase field, it is clear that the sharp Bragg reflections characteristic of the underlying fluorite average structure are accompanied by some of the 'satellite reflections' characteristic of the pyrochlore solid solution field. As the PrO1.5 content increases, these satel

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Koroleva, Mariia S., Aleksei G. Krasnov, and Irina V. Piir. "DOPING BISMUTH NIOBATES AS AN APPROACH TO OBTAINING HIGH-ENTROPY PYROCHLORES WITH DIELECTRIC PROPERTIES." Transactions of the Kоla Science Centre of RAS. Series: Engineering Sciences 3, no. 3/2023 (2023): 193–97. http://dx.doi.org/10.37614/2949-1215.2023.14.3.035.

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An approach to the obtaining of high-entropy compositions with the pyrochlore structure with dielectric properties based on substituted bismuth niobates is shown. A series of compositions has been synthesized, and the regions for the formation of compounds with the pyrochlore structure have been established. The optical and dielectric properties of the resulting compositions have been studied. It is shown that the samples are wide-gap semiconductors and the dielectric indices depend on the polarizability of the doped cations and the size of the agglomerates.

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Figueiredo, M. O. "Antimony oxides: the pyrochlore-type structure revisited." Acta Crystallographica Section A Foundations of Crystallography 61, a1 (2005): c496. http://dx.doi.org/10.1107/s0108767305079523.

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Shul’pina, I. L., N. N. Kolpakova, M. P. Shcheglov, and A. O. Lebedev. "Real structure of Cd2Nb2O7 pyrochlore single crystals." Technical Physics Letters 25, no. 7 (1999): 561–63. http://dx.doi.org/10.1134/1.1262553.

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